A ceramic chip having electrical characteristics of semiconductors such as thermistors, magnetic substances, and piezoelectrics, or a ceramic chip having electrical characteristics of dielectrics such as capacitors may be installed on a printed circuit board (PCB). To this end, for example, a metal lead wire or a metal lead frame may be soldered to an electrode of a ceramic chip, then, an insulation sealant may be formed on a portion connecting the ceramic chip to the lead wire or lead frame, then, a heat shrinkable tube may be fitted on an exposed portion of the lead wire or lead frame to form a ceramic chip assembly with the lead wire or lead frame electrically insulated except for its end, and then, the uninsulated end is soldered to a conductive pattern of a PCB, thereby electrically and mechanically connecting the ceramic chip and the PCB to each other. Alternatively, wires facing exposed ends of the lead wire of the ceramic chip assembly may be soldered or welded thereto, and thus, be electrically connected thereto.
Electrical and mechanical connection of such a ceramic chip assembly to a PCB should be facilitated, and the ceramic chip assembly should be lightweight, slim, compact, economical, and resistant to environment.
In addition, an insulating sealant should reliably seal and protect a ceramic chip and a lead wire from environment.
In addition, an exposed portion of a lead wire except for a portion to be soldered should be reliably insulated by an insulating material.
In addition, an exposed portion of a lead wire except for a portion to be soldered should be thin, flexible, and economically insulated.
In addition, an exposed portion of a lead wire except for a portion to be soldered should be insulated to be free from a crack due to bending.
FIG. 1 is a cross-sectional view illustrating a ceramic chip assembly in the related art. FIG. 2 is a cross-sectional view taken along line 2-2′ of FIG. 1.
Referring to FIG. 1, in a ceramic chip assembly 1, a cylindrical metal lead wire 20 is soldered to a ceramic chip 10, and is electrically insulated by an insulation sealant 40 such as an epoxy resin or glass. Although one wire as the lead wire 20 is illustrated in FIG. 1 that is a side cross-sectional view, the lead wire 20 is provided in a pair.
An exposed portion of the lead wire 20 connected to the ceramic chip 10 is exposed out of the insulation sealant 40, and is fitted in an insulation tube 30 that includes one of a PVC tube, a polyimide tube, or a Teflon tube.
As such, the exposed portion of the lead wire 20 out of the insulation sealant 40 is electrically protected by the insulation tube 30. When the exposed portion of the lead wire 20 is long, insulation of the exposed portion is important. For example, unless the exposed portion of the lead wire 20 is reliably insulated, an unnecessary contact between the ceramic chip assembly 1 and an adjacent part may occur, or moisture or water may be introduced to the ceramic chip 10 along the exposed portion of the lead wire 20. In particular, since an electrical performance of the ceramic chip 10 having electric characteristics of a semiconductor such as a thermistor is varied by moisture or water, the exposed portion of the lead wire 20 should be reliably insulated to prevent introduction of moisture and water to the ceramic chip 10 along the lead wire 20.
Referring to FIG. 2, since the insulation tube 30 receiving the lead wire 20 has a hole 32 with an inner diameter greater than the outer diameter of the lead wire 20, a space 32 formed between the insulation tube 30 and the lead wire 20 loosens coupling of the insulation tube 30 and the lead wire 20, and thus, the insulation tube 30 may be moved from a predetermined area of the lead wire 20, thereby degrading the workability of a subsequent process and requiring an additional process. Although the lead wire 20 is disposed in the center of the space 32 in FIG. 2, the lead wire 20 may be misaligned with the space 32.
Since the space 32 is disposed between the lead wire 20 and the insulation tube 30, water or moisture may be introduced to the ceramic chip 10 along the lead wire 20.
In addition, since the insulation tube 30 having a certain outer diameter is fitted on the lead wire 20, automation may be difficult, and manufacturing costs may be increased.
In addition, since the insulation tube 30 is thick, slimming of the ceramic chip assembly 1 may be difficult.
In addition, moisture or water may be introduced along a boundary between the insulation sealant 40 and the lead wire 20.
Alternatively, a heat shrinkable tube having an inner diameter greater than the outer diameter of the lead wire 20 may be fitted on the lead wire 20 and be shrunken by heat to insulate the exposed portion of the lead wire 20. However, in this case, since the heat shrinkable tube is shrunken by heat, automation may be difficult, and thus, manufacturing costs may be increased.
In addition, since the space 32 is formed between the lead wire 20 and the heat shrinkable tube, water or moisture may be introduced to the ceramic chip 10 along the lead wire 20.
In addition, since the heat shrinkable tube is thick, slimming of the ceramic chip assembly 1 may be difficult.
In addition, moisture or water may be introduced along a boundary between the insulation sealant 40 and the lead wire 20.
Alternatively, referring to FIGS. 3A and 3B, ceramic chip assemblies 3 and 4 include a thin insulation polymer coating layer 50 on the rest of the lead wire 20 except for both ends 21 and 22 of the lead wire 20. The insulation polymer coating layer 50 having a constant small thickness is continuously formed on the lead wire 20 to form an insulation wire such as an enamel wire, then, the insulation polymer coating layer 50 is partially removed from the ends 21 and 22 by heat, and then, the ceramic chip 10 is connected to the end 22 through an electrical adhesive member such as a soldering material, and is sealed by the insulation sealant 40, thereby forming the ceramic chip assemblies 3 and 4.
However, to this end, an enamel wire formed by continuously forming the insulation polymer coating layer 50 having a constant small thickness on the lead wire 20 is cut to a constant length, then, the insulation polymer coating layer 50 is partially removed from the ends 21 and 22 of the enamel wire, then, the ceramic chip 10 is manually soldered to the end 22, and then, the insulation sealant 40 is formed thereon. Thus, automation may be difficult, costs may be increased, and quality may be unstable.
In addition, moisture or water may be introduced along a boundary between the insulation sealant 40 and the insulation polymer coating layer 50.
In addition, there is no member for protecting the insulation sealant 40.